One more question about the Jag's tone control!

[thegreatbigsby]

Hey everybody!
Long time lurker, finally a member. Help from the hive mind needed and greatly appreciated! I hope nobody has to roll their eyes about this too hard - I know it's a common theme, but I can't find this specific question answered exactly.

I love my Jaguar. Swapped out the pots for 280k ones for better range, experimented a bit with different cap values - all good. But I can't help but ask myself if the infamous tone control could somehow be working more like it does in pretty much any other guitar. Right now it's affecting treble AND bass. It did that before I swapped pots, and from what I gather that's how it traditionally is in Jags. But I can't for the life of me figure out if it's possible to have it only affecting treble like in, say, a tele. I can solder a bit, but I'm not versed in electronics enough to figure it out myself. So here's hoping somebody can enlighten me...

Cheers!

[JSett]

If you want it to behave like a Telecaster tone control then it's just a case of rerouting the cap and wire connections to match a Tele system. Probably a 2 minute job once your iron has warmed up.

There's nothing fancy going on with either, they're just two different flavours of a passive low-pass filter.

[solfege]

As I understand it (and I wish I could remember where I read this), the whole thing ultimately has to do with the strangle switch (a high pass filter), which interacts with the the tone control on the lead circuit (low pass filter) in ways that requires that extra resistor in the Jag tone circuit which you don't find in the JM, the Tele, or pretty much anywhere else. Basically, that resistor is there to make the tone control behave usefully when the strangle switch is engaged.

So if that's right, there may be other effects of tweaking the tone circuit to removing that resistor, which would be the major change introduced by rewiring for a more 'conventional' tone circuit a la Tele or JM.

[jorri]

Well my bass Vi has no such resistor and a different custom JM wired differently certainly didn't need one as i bypassed tone when strangle engaged. Its on a dpdt slide so plenty scope for that. The bss vi does have a useless tone when engaged.

The difference is the 3pin vs 2pin ways of wiring an LPF. You get different results with a potential divider than just varying resistance, including impedance load and whether resistance in signal path. 3pin has volume loss yet doesn't go as resonant when turned down (see rhythm circuit), like a more effectively tuned LPF. 2pin has no loss because it creates a peak at cap's resonant frequency and sounds a bit wah-ish when at zero. JAG has a resistor that bridges the gap between them and changes the taper as well as things it may do to the strangle switch (it changes them as much as it does as a low-pass)

[solfege]

Well my bass Vi has no such resistor and a different custom JM wired differently certainly didn't need one as i bypassed tone when strangle engaged. Its on a dpdt slide so plenty scope for that. The bss vi does have a useless tone when engaged.

The difference is the 3pin vs 2pin ways of wiring an LPF. You get different results with a potential divider than just varying resistance, including impedance load and whether resistance in signal path. 3pin has volume loss yet doesn't go as resonant when turned down (see rhythm circuit), like a more effectively tuned LPF. 2pin has no loss because it creates a peak at cap's resonant frequency and sounds a bit wah-ish when at zero. JAG has a resistor that bridges the gap between them and changes the taper as well as things it may do to the strangle switch (it changes them as much as it does as a low-pass)

Thanks. That's helpful!

[timtam]

Interestingly, the 56k resistor is absent in the Am Pro jag, which also does not have the strangle switch; that, and the more obvious proximity of the resistor to the strangle evident in a vintage-style jag schematic (compared to a wiring diagram) has prompted the speculation that the resistor might be related to the strangle - see below. The Marr jag also has unconventional jag wiring somewhat like the Am Pro, but it has the strangle (in fact it has two) and it has the 56k resistor. As jorri points out the jag tone is traditionally wired as a voltage divider. It is wired that way in the Marr too. But in the Am Pro's tone circuit it's wired as a more conventional-style variable resistor. Maybe someone at Fender knows why the 56k was put there in 1962 and has been there ever since in vintage-style jags. Or maybe that knowledge has been lost in the sands of time.

Am Pro jag


Vintage-style jag

[ThePearDream]

As I understand vintage Jaguar wiring, the lead circuit controls works something like this:
the signal passes through the tone control first before going to the volume control. The tone is also wired up basically the same as the volume control, but with a cap to ground and the mysterious resistor. Well, the resistor is there to act as a jumper, so 56k of un-capacitated signal always gets through, and when the tone is turned down all the way, 56k still gets through to the volume control, rather than 0k. I'm not an expert by any means, so I could be way off. It seems to be a similar concept to a treble bleed on a volume control.

Anyway, as others said, OP should change to tele style tone wiring.

[thegreatbigsby]

Hey everybody,

thanks for all the replies. I now indeed tried to implement a more tele-ish wiring, and it seems to have worked. Only while having the strangle engaged the tone control does take away bass (or volume?), with the strangle off it works like a regular old tone control. So I can get some Jag-only type sounds with strangle engaged and tone rolled down a little, while having a (for me) usable way to tame treble (and only treble) with the strangle off.

Thanks all!